CN115283368A - Method for improving laser removal stability and efficiency of metal plate surface coating - Google Patents

Abstract

The present invention provides a method for improving the efficiency and stability of laser-removing metal plate coating, comprising: 1) fixing a sample on a workbench, and aligning the coated side with a laser cleaning head; 2) turning on a magnetic field Generating device, by passing a current into the coil, a corresponding magnetic field will be generated around the sample; 3) Turn on the pulsed laser, adjust the corresponding laser parameters to remove the coating on the surface of the sample; 4) Turn off the laser and the magnetic field generator, clean up 5) Observe whether the coating on the surface of the sample is removed cleanly, if not, repeat the above steps. Through the interaction between the external magnetic field and the plasma, the invention controls the aggregation and diffusion of the plasma, weakens the shielding effect of the plasma on the laser, and also weakens the eruption period and intensity of the plasma, so that the laser energy distribution is better. Uniformly and effectively improve the stability of laser-removed metal sheet coatings.

Description

A method to improve the stability and efficiency of laser removal of metal sheet surface coating

technical field

The invention relates to the field of advanced laser manufacturing; in particular, it relates to a method for improving the stability and efficiency of laser removal of the surface coating of metal plates.

Background technique

The coating on the surface of metal components will gradually age, crack, and fall off after a long period of service. When it is repaired and repainted, it is necessary to remove the coating on the surface of the part in advance. Compared with the traditional surface removal technology, laser removal, as a new type of surface removal technology, not only can achieve high-precision removal, but also has the advantages of non-contact, green, and high efficiency.

In the process of removing the coating, it mainly relies on the ablation effect between the laser and the coating. The laser makes the coating reach the gasification temperature and forms steam on the surface of the sample. The laser is irradiated on the steam and the surrounding air to make the steam part Laser energy is absorbed and ionized, forming a plasma. Plasma gathers above the coating, which will further absorb laser energy, produce shielding effect, and reduce the utilization efficiency of laser. At the same time, the gathered plasma will dissipate to the surrounding due to the expansion effect caused by high temperature. The process of gathering and diffusing the plasma will cause the fluctuation of the laser energy reaching the coating surface, increase the non-uniformity of the laser energy distribution, and affect the laser energy. Removed stability.

Contents of the invention

The object of the present invention is to provide a method for improving the stability and efficiency of laser removal of the surface coating of metal sheets.

The present invention is achieved through the following technical solutions:

The invention relates to a method for improving the stability and efficiency of laser removal of a metal sheet surface coating, comprising the following steps:

Step 1, fix the metal sheet 3 to be removed on the workbench 4, and align the side with the coating 2 with the laser cleaning head 1;

Step 2, open the magnetic field generator, which includes: an insulating shell 5, an iron core 7 and a magnetic induction coil 6; by passing current into the magnetic induction coil 6, a corresponding magnetic field is generated around the sample;

Step 3, turn on the pulse laser, adjust the corresponding laser parameters to remove the coating on the surface of the sample;

Step 4, turn off the laser and the magnetic field generator, clean up the residual waste on the surface of the sample, and take out the sample;

Step 5, observe whether the coating on the surface of the sample is removed, if not, repeat the above steps.

Preferably, in step 1, the coating 2 is polyurethane coating, epoxy coating, fluorocarbon metal coating, acrylic metal coating, wear-resistant coating, thermal barrier coating, wave-absorbing coating, etc. Commonly used coatings.

Preferably, in step 1, the metal plate 3 is made of aluminum alloy, titanium alloy, stainless steel and other metal materials.

Preferably, in step 1, the thickness of the metal plate 3 is 2mm-5cm.

Preferably, in step 2, the current is a stable direct current, the magnetic field generated by the magnetic induction coil 6 is a constant magnetic field, and the current range is 0A-10A.

Preferably, in step 3, the laser wavelength range of the pulsed laser is 500nm-10.6μm, the output power range is 10%-100%, the laser pulse width range is 10ns-500ns, and the pulse frequency range is 10Hz-1000kHz.

Preferably, in step 3, the pulsed laser is CO ₂ laser, Nd:YAG laser or fiber laser, the pulse power of the pulsed laser is 10W-1000W; the pulsed laser is: Ouling NFL-E200-4 pulsed fiber Laser or Ouling NFL-D200-1.3 pulsed fiber laser.

Preferably, in step 3, the laser spot of the pulsed laser is processed with a circular laser spot or a square laser spot.

The magnetic field generator of the present invention is: KANETEC electromagnetic KMD-15C magnetic field generator or KANETEC lifting magnet KE-5B magnetic field generator.

Preferably, in step 3, the laser beam of the pulsed laser arranges the laser energy on the surface of the sample in a two-dimensional form through the vibrating mirror, and the scanning speed is 500mm/s-5000mm/s, and the S-shaped scanning method is adopted.

The present invention has the following advantages:

(1) Compared with the surface removal technology of the traditional metal sheet surface coating, the present invention has the advantages of high specific efficiency, high precision, non-contact, environmental protection, and no damage to the substrate.

(2) The present invention controls the aggregation and diffusion of the plasma through the interaction between the external magnetic field and the plasma, weakens the shielding effect of the plasma on the laser, and then improves the efficiency of laser removal; the external magnetic field of the present invention can also weaken the plasma The eruption period and intensity of the body make the laser energy distribution more uniform and effectively improve the stability of laser removal of metal sheet coatings.

(3) The method involved in the present invention has a wide range of applications, and can be applied to other laser processing fields such as laser welding and laser engraving, and has important significance for improving the stability and efficiency in the laser processing process.

Description of drawings

Fig. 1 is the schematic diagram of the method involved in the present invention;

In the figure, 1-laser cleaning head, 2-coating, 3-metal plate, 4-working table, 5-insulating shell, 6-magnetic induction coil, 7-iron core.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. It should be noted that the following implementation examples are only further descriptions of the present invention, but the protection scope of the present invention is not limited to the following examples.

Example 1

This embodiment relates to a method for improving the stability and efficiency of laser removal of the metal sheet surface coating, as shown in Figure 1, the steps are as follows:

The first step is to cut the metal plate 3 of the 2024 aluminum alloy plate coated with acrylic polyurethane coating to a suitable size, fix the sample to be cleaned on the workbench 4, and place the side with the coating 2 Align the laser cleaning head 1.

The second step is to open the magnetic field generator, which includes: an insulating shell 5, an iron core 7 and a magnetic induction coil 6; by passing current into the magnetic induction coil 6, a corresponding magnetic field is generated around the sample;

The third step is to use a 100W fiber laser to remove the polyurethane coating, use the X and Y vibrating mirrors to arrange the laser energy on the surface of the sample in a two-dimensional form, and select the laser parameters: the laser wavelength is 1064nm, and the output power is 50%. , the pulse width is 100ns, the repetition frequency is 100kHz, the scanning speed is 2500mm/s, the line spacing is 0.025mm, the scanning route is S-shaped, the laser spot is circular, and the spot diameter is 0.05mm.

The fourth step is to turn off the laser and the magnetic field generator, clean up the residual waste on the surface of the sample, and take out the sample;

The fifth step is to observe whether the coating 2 on the surface of the sample is completely removed, if not, repeat the above steps.

Example 2

This embodiment relates to a method for improving the stability and efficiency of laser removal of the metal sheet surface coating, as shown in Figure 1, the steps are as follows:

The first step is to wire-cut the metal plate 3 of the 5052 aluminum alloy plate coated with epoxy zinc yellow coating to a suitable size, fix the sample to be cleaned on the workbench, and place the coated 2 Aim at the laser cleaning head 1.

The second step is to open the magnetic field generator, which includes: an insulating shell 5, an iron core 7 and a magnetic induction coil 6; by passing current into the magnetic induction coil 6, a corresponding magnetic field is generated around the sample;

The third step is to use a 30W fiber laser to remove the epoxy zinc yellow coating, use the X and Y vibrating mirrors to arrange the laser energy on the surface of the sample in a two-dimensional form, and select the laser parameters: the laser wavelength is 1064nm, the output power 30%, the pulse width is 1μs, the repetition frequency is 50kHz, the scanning speed is 1200mm/s, the line spacing is 0.02mm, the scanning path is S-shaped, the laser spot is circular, and the spot radius is 0.039mm.

The fourth step is to turn off the laser and the magnetic field generator, clean up the residual waste on the surface of the sample, and take out the sample;

The fifth step is to observe whether the coating 2 on the surface of the sample is completely removed, if not, repeat the above steps.

Example 3

This embodiment relates to a method for improving the stability and efficiency of laser removal of the metal sheet surface coating, as shown in Figure 1, the steps are as follows:

The first step is to wire-cut the TC4 titanium alloy metal plate 3 coated on the surface to a suitable size, fix the sample to be cleaned on the workbench, and align the side with the coating 2 for laser cleaning head.

The second step is to open the magnetic field generator, which includes: an insulating shell 5, an iron core 7 and a magnetic induction coil 6; by passing current into the magnetic induction coil 6, a corresponding magnetic field is generated around the sample;

The third step is to use a 300W Nd:YAG laser to remove the polyurethane coating, use the X and Y vibrating mirrors to arrange the laser energy on the surface of the sample in a two-dimensional form, and select the laser parameters: the laser wavelength is 1064nm, and the output power is 80%, the pulse width is 6ns, the repetition frequency is 30kHz, the scanning speed is 2000mm/s, the line spacing is 0.5mm, the scanning route is S-shaped, the laser spot is circular, and the spot radius is 10mm.

The fourth step is to turn off the laser and the magnetic field generator, clean up the residual waste on the surface of the sample, and take out the sample;

The fifth step is to observe whether the coating 2 on the surface of the sample is completely removed, if not, repeat the above steps.

Example 4

This embodiment relates to a method for improving the stability and efficiency of laser removal of the surface coating of a metal sheet assisted by an external magnetic field, as shown in Figure 1, and the steps are as follows:

The first step is to wire-cut the metal plate 3 of the 304 stainless steel plate coated with epoxy base coating 2 to a suitable size, fix the sample to be cleaned on the workbench, and place the side with the coating 2 Align the laser cleaning head.

The second step is to open the magnetic field generator, which includes: an insulating shell 5, an iron core 7 and a magnetic induction coil 6; by passing current into the magnetic induction coil 6, a corresponding magnetic field is generated around the sample;

The third step is to use a 500W CO ₂ laser to remove the polyurethane coating, use the X and Y vibrating mirrors to arrange the laser energy on the surface of the sample in a two-dimensional form, and select the laser parameters: the laser wavelength is 1064nm, and the output power is 80 %, the pulse width is 100ns, the repetition frequency is 10kHz, the scanning speed is 3000mm/s, the line spacing is 0.2mm, the scanning route is S-shaped, the laser spot is circular, and the spot radius is 0.96mm.

The fourth step is to turn off the laser and the magnetic field generator, clean up the residual waste on the surface of the sample, and take out the sample;

The fifth step is to observe whether the coating 2 on the surface of the sample is completely removed, if not, repeat the above steps.

The above-mentioned embodiments 1-4 are compared with the results of the blank test for magnetic field strength B/T, removal depth, ablation diameter, ablation maximum height difference, removal efficiency, and surface roughness after removal. The results are shown in Table 1:

Table 1

From the test data of the above-mentioned table 1, it can be seen that the magnetic field strength B/T, removal depth, ablation diameter, ablation maximum height difference, removal efficiency, and surface roughness after removal of the embodiments 1-4 involved in the present invention are all average. It is higher than the value of the blank control, thus it can be proved that the present invention controls the aggregation and diffusion of the plasma through the interaction between the external magnetic field and the plasma, and weakens the shielding effect of the plasma on the laser; it can also weaken the plasma The eruption period and intensity make the laser energy distribution more uniform and effectively improve the stability of laser removal of metal sheet coating.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims (9)

1. A method for improving the stability and efficiency of laser removal of a coating on the surface of a metal plate is characterized by comprising the following steps:

step 1, fixing a metal plate (3) to be removed on a workbench (4), and aligning one surface with a coating (2) to a laser cleaning head (1);

step 2, turning on a magnetic field generator, which comprises: the magnetic induction coil comprises an insulating shell (5), an iron core (7) and a magnetic induction coil (6); current is introduced into the magnetic induction coil (6) to generate a corresponding magnetic field around the sample piece;

step 3, turning on the pulse laser, and adjusting corresponding laser parameters to remove the coating on the surface of the sample piece;

step 4, turning off the laser and the magnetic field generator, cleaning the residual waste on the surface of the sample piece, and taking out the sample piece;

and 5, observing whether the coating on the surface of the sample piece is completely removed or not, and if not, repeating the steps.

2. The method for improving the laser removal stability and efficiency of the coating on the surface of the metal plate according to claim 1, wherein in the step 1, the coating (2) is a polyurethane coating, an epoxy coating, a fluorocarbon metal coating, an acrylic metal coating, an abrasion-resistant coating, a thermal barrier coating, or a wave-absorbing aerospace common coating.

3. The method for improving the laser removal stability and efficiency of the surface coating of the metal plate as claimed in claim 1, wherein in the step 1, the metal plate (3) is made of metal materials of aluminum alloy, titanium alloy and stainless steel.

4. The method for improving the laser removal stability and efficiency of the surface coating of the metal plate material according to claim 1, wherein in the step 1, the thickness of the metal plate material (3) is 2mm-5cm.

5. The method for improving the laser removal stability and efficiency of the surface coating of the metal plate material according to claim 1, wherein in the step 2, the current is a stable direct current which is in the range of 0A-10A; the magnetic field generated by the magnetic induction coil (6) is a steady magnetic field.

6. The method for improving the laser removal stability and efficiency of the coating on the surface of the metal plate material according to claim 1, wherein in the step 3, the laser parameters are specifically: the wavelength of the laser is 500nm-10.6 μm, the output power is 10% -100%, the pulse width of the laser is 10ns-500ns, and the pulse frequency is 10Hz-1000kHz.

7. The method for improving laser removal stability and efficiency of surface coating on metal plate according to claim 1, wherein in step 3, the pulsed laser is CO ₂ YAG laser or fiber laser, the pulse power of the pulse laser is 10W-1000W.

8. The method for improving the laser removal stability and efficiency of the coating on the surface of the metal plate material according to claim 1, wherein in the step 3, the light spot of the pulse laser is a circular laser light spot or a square laser light spot.

9. The method for improving the laser removal stability and efficiency of the coating on the surface of the metal plate according to claim 1, wherein in the step 3, the laser beam of the pulse laser arranges the laser energy on the surface of the sample in a two-dimensional form through a vibrating mirror, the scanning speed is 500mm/S-5000mm/S, and an S-shaped scanning mode is adopted.

Images